We are continuing experiments on the synergy of immunologic injury to arteries and hyperlipidemia in the pathogenesis of atherosclerosis in the rabbit. We are studying the effect of regenerated endothelium on lipid accumulation in the walls of arteries following injury with special attention to changes in glycosaminoglycans. The role of atopic or IgE mediated allergy in producing vascular permeability and abnormalities of cardiac function is being studied with special attention to highly allergenic antigens that we have purified from tobacco leaves and cigarette smoke. The relationship of immunologically and otherwise induced endothelial injury to the pathogenesis of arteriosclerosis is being evaluated. We are continuing investigations on contractile and relaxing proteins of the cardiovacular system with emphasis on regional differences in endothelium and the autoantigenicity of these proteins. We are investigating the pathogenesis of glomerulonephritis induced experimentally with group A streptococci. These studies are aimed at understanding the relationship of maternal infection and fetal immunization with streptococci to the development of these sequellae and to the elucidation of the nature of nephritogenicity.